Cooling apparatus for electric lamps



Sept. 8, 1942. P. B. DAVIS 2,295,031

' COOLING APPARATUS FOR ELECTRIC LAMPS V Filed Aug. 3, 1940 (5 Z7 Z2 M 38- 33 I lnvervbov: 25 Paul B. Davis,

5 His Afiotnegof the same.

Patent ed Set. 8, 3M2

UNITED STATES PATENT" OFFICE coomNG APFA% non ntnc'rmc.

Paul B, Davis, East Cleveland, Ohio, assignor to GeneralElectric Company, a corporation of New York Application August 3, 1940, Serial No. 350,885

7 Claims. (,cl. 24o' 11.4)

My invention relates in general to high inl0. One end of the said inner tube H is sealed tensity light sources particularly of the small to the outer tube In at a point adjacent the water high-pressure mercury arc type, such as deintake end of the latter. scribed and claimed in U. S. Patent No. 2,094,694, Secured to the intake and outlet ends respec- Cornelis Bol at 11., issued October 5, 1937, and tively of the glass tube ID are a copper thimble l2 assigned to the assignee of the present invention. and a copper collar l3. The said thimble l2 and More particularly, my invention relates to a collar 3 are sealed by fusion to the ends of the water-cooling arrangement or jacket for one of glass tube III in accordance with the disclosure such lamps. I in U. S. Patent No. 1,294,466, Housekeeper, issued High-pressure mercury vapor lamps of the February 18, 1919. Such a glass-to-metal seal type referred to above are provided with relathus provides a positive water-tight connection tively small quartz tubes of the order of 40 mm. between the glass tube l0 and .thethimble l2 and or so in length and having an outside diameter collar l3. 1 of about 6 mm. and a bore of about 2 mm. In The thimble I2 is provided with an outwardly lamps of such small volume operating with rela- 16 extending integral intake tube H of reduced tively high power inputs of the order of 800 to diameter and disposed in axial alignment with 1000 watts and above, it is necessary'to effecthe glass tube l0. Secured within the copper tively cool the lamp in order to dissipate the relaintake tube It is a resilient lamp contact I 5 comtively large energy input within the small bulb prising a brass plunger l6 having at its innervolume and prevent softening of the lamp bulb. most end a head I! provided with a conical seat It is not suflicient merely to place the lamp in a or socket 8 in which a terminal I!) of the lamp bath of water. Instead, the water must be passed 20 is received. Said contact 5 further comprises over the lamp with enough velocity to prevent a brass sleeve or socket support member 2| 'sethe formation of steam bubbles on the surface cured to the intake tube It and through which of the quartz bulb. Steam bubbles do not conthe plunger l6 slidably extends, and'a stainless duct away the heat fast enough to prevent oversteel helical compression spring 22 concentrically heating of the lamp, so that their presence may mounted on the plunger it between the head I! result in the early failure of the lamp. thereof and the inner end of the sleeve 2|. At its One object of my invention is to provide an outer end, the. plunger is provided with a transimproved liquid-cooling single-unit mounting arversely extending stop pin 23 which abuts against rangement for small tubular electric lamps which the outer end of sleeve 2| to thereby lock the is simple in construction and effective in operaplunger within the said sleeve. 'As shown partion. ticularly in Fig. 4, the sleeve 2| is made from a Another object of my invention is to provide a bar of rectangular cross-section the corners of liquid-cooling single-unit mounting arrange- 5 which are ground fiat, as indicated at 24, so as ment for small tubular electric lamps which will to fit tightly against the inner wall of the intake permit easy replacement of the lamp upon failure tube 4. To insure that the sleeve 2| is positively secured in place in the intake tube M, the flat- Further objects and advantages of my inventened corners 24 of the sleeve are preferably tion will appearv from the ,following description 4 soldered to the said tube. The spaces 25 between of species thereof and from the accompanying the sides of the sleeve 2| and the surrounding indrawing in which: take tube l4 provide ample passageways forthe' Fig. 1 is a longitudinal section of a'liquid-cool flow of the cooling liquid through the intake tube ing single-unit mounting arrangement comprisinto the glass tube I0 surroundingthe lamp. ing my invention; and Figs. 2, 3 and 4 are trans- However, the narrower sides 26 of the sleeve 2| verse sections on the lines 22, 3-3, and 4-4 are preferably formed concave, as shown inFig. 4. I

respectively, on an enlarged scale. to thereby increase the cross-section of the spaces Referring to the drawing, the liquid-coolin between such'sides and the intake tube. device here s own c mprises a cylindrical jacket Electrical connection to the resilient contact o tuben of light transmitting he te is I5 is made by means of a brass connector ring 21 material, preferably of glass such as that comfitting on the intake tube It against the thimble mercially known as -Pyrex. The said glass tube. l2 thereof and secured in place on said tube H In is provided with an inner velocity tube II, also by a, plurality of set screws 28, and a brass terof a heat-resisting glass, whichis disposed conminal connector 29 threaded into the said concentrically within and spaced from the outer tube nector ring 21. To prevent any possibility oi electrical shock, the metal {said tube 33 and 33 is provided with thimble I! and connector ring 21 are enclosed in an insulating cap 33, and the terminal connector 33 encased in an insulatingbushingfl. Thecap3lissecuredto the conector ring 11, and the bushing 3| to the cap 33, by means of thethreaded terminal connector 33. The exposed take tube It extending out beyond the cap 33 is enclosed by the rubber water-inlet hose (not shown) during the operation of the device, thus completing the insulation of all the metal parts at the intake end of the device. I

Surrounding the outer end of the copper collar l3 at the outlet end of the device is a brass sleeve 32 which is soldered to the copper collar l3 so as to provide a water-tight connection therebetween. The outer periphery of the brass sleeve 33 is threaded for engagement with a knurled brass closure cap 33 which engages an outwardly. turned flange 34 on an outlet tube 33 and pre ses the same against a rubber gasket 33 inserted between the sleeve 32 and the flange 3|, thus securing the outlet'tube 33 in place and providing a water-tight connection between the u the brass sleeve 32. The outer end of the copper collar 13 is formed 9 with an lfltlllned annular flange :1 (Fig. 3) on which a stationary lamp contact 33 is mounted.

The said contact 33 comprises a brass stem 33 having a longitudinally slotted socket portion 43.

at its inner end in which the lamp terminal I! is securely held, and a stud portion ll of reduced diameter extending outwardly from the socket portion 33. Secured on said stud portion ll by a press fit and resting against the socket portion 43 is a perforated contact mounting disc 43. The said disc seats on the annular flange 31 on the collar l3, and is provided with a plurality of circular openings l3, preferably four in number and arranged in a circle about the center of the The said openings 33 provide passageways between the interior of the glass tube l3 and the outlet tube 33 through which the cooling liquid can pass. The socket portion 43 of the stationary contact 33 is provided with a transverse locking lug or pin II which is spaced inwardly from the disc 33 a distance slightly greater than the thickness of the annular flange 31 so that the latter can enter the spacebetween the said lug and the disc 43. As shown particularly in Fig. 3, the annular flange 31 is provided with diametrically opposite radial slots or notches 45 through which the locking pin 44 is inserted during the mounting of the stationary contact 33 on the annular flange 31 of the copper collar I3.

Mounted centrally within the glass tube It an extending through the velocity tube II is a hightype, such as described and claimed in the aforesaid Bol et al. Patent No. 2,094,694 and comprisminals I! are mounted between the resilient and stationary sockets l3 and 43 respectively, the latter being so spaced,when the device is completely assembled, as to cause a compression of the spring 22 of the resilient lamp contact IS. in this manner a good electrical contact is insured at all times between the socket l3 and the associated lamp terminal is.

To insure a good electrical connection at all times between the stationary lamp contact 38 and the brass outlet tube 35 to which electrical connection is made,

atruncated conical helical portion of the metal inouter end, the sprin compression spring I, of stainless steel, extending inwardly from the said tube 33 and engaging the disc 33 of the stationary contact 33. At its 41 is provided with a cylindrical closed-wound portion 03 which extends into the outlet tube 33 and tightly fits'within the same so as to be securely held therein. When the closure cap 33 is screwed down onto the brass sleeve 33 so as to secure the outlet tube 33 thereto, the conical spring .41 engages the disc 42 and is compressed by the inward movement of the outlet tube. The compressive force of spring 41 being greater than that 'of the spring. I! in the resilient lamp contact I, the disc 32 is forced against the annular .fiange .31 withconsiderable pressure. The result-is that a good contact is provided between the stationary contact 38 and the brass outlet tube 3! at all times.

Electricalconnection to the outlet tube 33 is made by a combination mounting support and connector member is of brass comprising a collar 33 fitting around the outlet tube and secured thereto by a plurality of set screws 3 l, and a sup port arm 53 extending transversely therefrom and disca conical socket is in the threaded at its outer end for engagement with mounting nuts 53. Screwed to the arm 52 is a terminal lug 54 to which the lead 35 from the current source is soldered. The mounting support ll is preferably secured to the outlet tube 33 in a position with the collar 50 against the closure cap 33 so as to lock the cap between the said collar and the flange 34 of the outlet tube 33.

To assemble the lamp end terminal I! of the lamp is inserted in the slotted socket ll of the stationary contact 33 after which the lamp, together with the attached contact 33, is introducd into the glass tube I I 0 through the open outlet end thereof with the free lamp end terminal first so that'the latter engages the resilient lampcontact I. Then with the locking pin 44 in alignment with the notches 45 in the annular flange 31, the lamp and its attached contact 33 are moved inwardly a still further amount against the resistance of the compression spring 22 of the resilient contact I! until the locking pin passes through the said notches 45, after which the stationary contact pressure mercury vapor lamp 33 of the capillary lamps in case of a failure thereof.

is rotated a slight amount one way or the other. preferably 90 or thereabouts, so that the locking pin underlies the annular flange 3'l, as'shown in Fig. 3, and .is pressed thereagainst by the recoiling action of spring 12. The closure cap 33, with the attached outlet tube 35, is then screwed down tight onto the brass sleeve 32 so as to complete the assemblage. From the above, it is evident that the construction according to the invention affords easy access to the device for changing The velocity tube H is made of such a diameter as to. provide a relatively small radial clearance 33 (Fig. 2) from the lamp 20 of about 1 mm. or thereabouts through which the cooling water must flow. Because of this restricted cross-section of the cooling water, the electrical conductivity thereof between the exposed lamp terminals I9 is kept at a relatively low value insuflicient to cause any material interference with the v proper operation of the lamp. Thus, where a 1000 watt lamp is enclosed by a velocity tube l l providing an annular space of about 1 mm. around the lamp, the current through the cooling water is only about 10 to 25 milliamperes.- The use of the the inner end of the outlet tube Velocity tube l I thus permits the exposure of both terminals I! of the lamp 20 to the cooling liquid and consequently permits the use of the easily 20 within the device, one

interchangeable lamp mounting arrangement disclosed hereinabove.

' The velocity tube also serves to impart a relatively high velocity to the cooling water. Because of the restricted annular cross-section of 'the cooling water, more than ample water velocity is attained to prevent the undesirable formation of steam bubbles with a water flow of about three liters per minute, Thus, with an annular passage about one millimeter wide around a 1000 watt lamp, a water flow of about three liters per minute gives ample velocity and a temperature rise less than 3 C. The use of the velocity tube ll thus has made it possible to use a smaller amount of cooling water than that heretofore necessary to efiectively cool a given lamp, because it is not the amount of water, but merely the surface velocity that matters. The criterion for proper cooling is that the speed of fiowshould be great enough to prevent the formation of any steam bubbles.

, In the operation of the device, the intake and outlet tubes l4 and 35 respectively are connected to rubber inlet and outlet hoses (not shown) for the cooling liquid. After the'fiow of the cooling liquid through the device is initiated, the electrical circuit through the lamp 20 may then be closed so as to start the operation thereof.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A liquid-cooling mounting device for a high intensity tubular electric lamp comprising a tubular glass jacket through which the cooling liquid is adapted to be circulated, cylindrical metal .sleeves sealed by fusion to the opposite ends of said glass jacket, and a pair of opposed lamp sockets supported by said metal sleeves in such a manner as to leave passages through said sleeves for flow of the cooling liquid therethrough,

2. A liquid-cooling mounting device for a high intensity tubular electric lamp comprising a tubular glass jacket through which the cooling liquid isadapted to be circulated, cylindrical metal elements sealed by fusion to the opposite ends of said lass jacket, a pair of opposed lamp sockets' supported by said metal elements and centrally located therein, and a glass velocity tube disposed centrally within the said glass' jacket and sealed at one end to said glass jacket by fusion so as to close off the annular space between said velocity tube and said tubular glass jacket, said velocity tube closely surrounding the lamp for the greater part of its length.

3. A liquid-cooling mounting device for a high intensity tubular electric lamp comprising a tubular glass jacket through which the cooling liquid is adapted to be circulated, and cylindrical metal sleeves sealed by fusion to the opposite ends of said glass jacket, one of said metal sleeves carrying a readily detachable closure cap and being provided with support means for a lamp socket so mounted in said sleeve as to leave a passage therethrough for flow of cooling liquid, said lamp socket firmly gripping the lamp and being readily disengageable from said support means for withdrawal froin the jacket, and a second socket mounted within. the -other metal sleeve in such a manner as to leave a passage therethrough for fiow of cooling liquid.

4. A liquid-cooling mounting device for high intensity tubular electric lamps comprising a tubular glassjacket through which the cooling liquid is adapted to be circulated, metal sleeves sealed by fusion to the opposite ends of said glass jacket and each provided with a tubular extension communicating with the interior of said glass jacket and-through which the cooling liquid is circulated into and out of said glass jacket, and a pair of opposed lamp sockets disposed within said device at the opposite ends thereof, at

' least one of said sockets bein removably mounted on that metal sleeve at the corresponding end of said device in such a manner as to leave a passage therethrough for flow of cooling liquid.

5. A liquid-cooling mounting device for high intensity tubular electric lamps comprising a tubular glass jacket through which the cooling liquid is adapted to be circulated, metal .sleeves sealed by fusion to the opposite ends of said glass jacket, one of said metal sleeves having a t'ubu-- lar extension integral therewith and the other of said sleeves having a similar tubular extension separable therefrom, said extensions communicating with the interior of said glass jacket for the passage of the cooling liquid thereinto and therefrom, and means co-operating with the said other metal sleeve for securing said separable extension to the said other metal sleeve so as to form a liquid-tight joint therebetween, a fixed socket mounted in said first-mentioned metal sleeve, and a second socket removably mounted in the said other sleeve.

6. A liquid-cooling mounting device for high intensity tubular electric lamps comprising a tubular glass jacket through which the cooling liquid is adapted to be circulated, metal elements sealed by fusion to the opposite nds of said glass jacket and each provided with a tubular extension communicating with the interior of said glass jacket and through which the cooling liquid is circulated into and out of said glass jacket, and a pair of opposed sockets disposed within said device at the opposite ends thereof, at least one of said sockets comprising a socket support member disposed within that tubular extension at the corresponding end of said device and rigidly secured to said extension so as to form an integral part therewith, said socket support member having at least one of its sides spaced from the inher wall of said tubular extension so as to provide a passageway for the flow of the cooling liquid through said extension.

7. A liquid-cooling mounting for an elongated electric lamp having a contact terminal at each end, comprising a tubular glass jacket, a metal sleeve member 'at one end of said jacket having one of its ends fused directly to said jacket, a socket member mounted in said sleeve member in such manner as to leave a passage through the sleeve member for flow of cooling liquid, a second metal sleeve member at the other end of said jacket having one of its ends fused directly to said jacket, a second socket member mounted within said second sleeve member in a readily PAUL B. DAVIS. 

